The scenario is familiar: the new high-performance machine has been delivered and installed and should now pay for itself as quickly as possible – but the material-flow remains unchanged. The responsible persons should, however, also invest money in this area in order to ensure that the performance of the new machine can be fully utilised. A good example of this is the trading company Schmidt + Bartl GmbH in D-78052 Villingen-Schwenningen, which not only invested in a new sheet saw and a new box-storage system for the sheets, but also in a new vacuum handling device from the vacuum specialist J. Schmalz GmbH in D-72293 Glatten. The reasons for this were as manifold as the tasks to be executed, since the company sells semi-finished plastic parts, plastic pipes and various elastomers and this means that it has to cut customer-specific pieces from large and heavy sheets of material such as POM (polyoxymethylene) or PC (polycarbonate). The sheets are received in the standard formats of 1000 x 500 mm, 2000 x 1000 mm or 3000 x 2000 mm, are up to 90 mm thick and weigh up to 120 kg. In the past, two persons and a fork lift truck were necessary to transfer the larger sheets from the storage area to the sawing machine, while smaller sheets were moved manually by the two workers. The introduction of the new box-storage system with higher side-walls also made manual removal of the sheets even more difficult.

Vacuum lifting device handles several tasks

With the vacuum lifting device from Schmalz, the company was able to solve all of its tasks in the handling of the sheets. Furthermore, one person can now remove the sheets from the storage area, move them to the machine and position them on the machine table with the aid of the vacuum lifting device. This lifting device, designed for suspension from a crane, is the basic version of one of the many different models in the VacuMaster series. The vacuum lifting device VM-BASIC-500-H-6-2400 is designed for loads weighing up to 500 kg and is equipped with three cross-beams, each 800 mm long, and six suction pads. Thanks to extended suction-pad mountings, which are also flexible and spring-mounted, it is easy to reach down into the storage boxes and remove complete or partial sheets. For this, the operator simply assumes the gripping and removal position with the aid of the operator handle. Once the load has been gripped, he can lift it with the chain hoist, move it to its new position and lower it again with the chain hoist. A special feature of the gripper is that suction pads which are not in contact with the load can be deactivated by moving a manual slide valve. This makes it easier to quickly and safely grip smaller or partial sheets.

Summary

The vacuum lifting device is suspended from a robust slewing column crane. A 4- metre jib and a slewing angle of 270° permit the crane to cover a large working area. The overall height of the crane is 3200 mm and the lower edge of the jib is 2600 mm above floor level, providing sufficient lifting height for the intended application. After a short familiarisation period, three workers are now using the vacuum lifting device and would not like to have to do without it, since it makes their work far easier. The sawing machine and the lifting device are used eight hours per day. Execution of orders is now easier and faster and presents fewer hazards for the health of the workers. There is virtually no damage to the surfaces of the workpieces. Unproductive waiting times on the sawing machines, except for the actual changing of the sheets and the removal of the sawn parts, are now a thing of the past.